AstraZeneca and Amgen today announced high-level results from the SOURCE Phase III trial which assessed the efficacy and safety of the potential new medicine tezepelumab compared to placebo in 150 severe asthma patients who required maintenance use of oral corticosteroids (OCS) on top of standard of care (SoC).

The 48-week trial did not meet the primary endpoint of a statistically significant reduction in the daily OCS dose, without loss of asthma control, with tezepelumab compared to placebo. Tezepelumab’s effect on other efficacy parameters was similar to those observed in previous trials, including the registrational Phase III NAVIGATOR trial.

Mene Pangalos, Executive Vice President, BioPharmaceuticals R&D, said: “Based on the totality of evidence, including the compelling exacerbation reduction results seen in the registrational NAVIGATOR Phase III trial and the PATHWAY Phase IIb trial, we remain confident that tezepelumab has the potential to improve care for a broad population of severe asthma patients. Our initial analysis of SOURCE in oral corticosteroid-dependent asthma indicates that the trial design may have contributed to the result of the primary endpoint. We are in the process of further analysing the data from SOURCE and look forward to sharing these results with the medical community.”

The safety profile of tezepelumab in the trial was consistent with previous trials. Detailed results from the SOURCE trial will be presented at a forthcoming medical meeting.

On 10 November 2020, AstraZeneca and Amgen announced positive results from the NAVIGATOR Phase III trial which met the primary endpoint and demonstrated a statistically significant and clinically meaningful reduction in the annualised asthma exacerbation rate (AAER) in a broad population of patients with severe asthma, including those with low levels of eosinophils.

Tezepelumab is a potential first-in-class medicine that blocks the action of thymic stromal lymphopoietin (TSLP), an epithelial cytokine that plays a key role across the spectrum of asthma inflammation.1,2 Tezepelumab is being developed by AstraZeneca in collaboration with Amgen.